159bd9dedSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
21da177e4SLinus Torvalds /*
31da177e4SLinus Torvalds * Copyright (C) 2004, OGAWA Hirofumi
41da177e4SLinus Torvalds */
51da177e4SLinus Torvalds
68c540a96SDavid Woodhouse #include <linux/blkdev.h>
7f663b5b3SWentao Wang #include <linux/sched/signal.h>
8edb0872fSChristoph Hellwig #include <linux/backing-dev-defs.h>
99e975daeSOGAWA Hirofumi #include "fat.h"
101da177e4SLinus Torvalds
111da177e4SLinus Torvalds struct fatent_operations {
121da177e4SLinus Torvalds void (*ent_blocknr)(struct super_block *, int, int *, sector_t *);
131da177e4SLinus Torvalds void (*ent_set_ptr)(struct fat_entry *, int);
141da177e4SLinus Torvalds int (*ent_bread)(struct super_block *, struct fat_entry *,
151da177e4SLinus Torvalds int, sector_t);
161da177e4SLinus Torvalds int (*ent_get)(struct fat_entry *);
171da177e4SLinus Torvalds void (*ent_put)(struct fat_entry *, int);
181da177e4SLinus Torvalds int (*ent_next)(struct fat_entry *);
191da177e4SLinus Torvalds };
201da177e4SLinus Torvalds
2198283bb4SOGAWA Hirofumi static DEFINE_SPINLOCK(fat12_entry_lock);
2298283bb4SOGAWA Hirofumi
fat12_ent_blocknr(struct super_block * sb,int entry,int * offset,sector_t * blocknr)231da177e4SLinus Torvalds static void fat12_ent_blocknr(struct super_block *sb, int entry,
241da177e4SLinus Torvalds int *offset, sector_t *blocknr)
251da177e4SLinus Torvalds {
261da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
271da177e4SLinus Torvalds int bytes = entry + (entry >> 1);
280afa9626SOGAWA Hirofumi WARN_ON(!fat_valid_entry(sbi, entry));
291da177e4SLinus Torvalds *offset = bytes & (sb->s_blocksize - 1);
301da177e4SLinus Torvalds *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
311da177e4SLinus Torvalds }
321da177e4SLinus Torvalds
fat_ent_blocknr(struct super_block * sb,int entry,int * offset,sector_t * blocknr)331da177e4SLinus Torvalds static void fat_ent_blocknr(struct super_block *sb, int entry,
341da177e4SLinus Torvalds int *offset, sector_t *blocknr)
351da177e4SLinus Torvalds {
361da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
371da177e4SLinus Torvalds int bytes = (entry << sbi->fatent_shift);
380afa9626SOGAWA Hirofumi WARN_ON(!fat_valid_entry(sbi, entry));
391da177e4SLinus Torvalds *offset = bytes & (sb->s_blocksize - 1);
401da177e4SLinus Torvalds *blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
411da177e4SLinus Torvalds }
421da177e4SLinus Torvalds
fat12_ent_set_ptr(struct fat_entry * fatent,int offset)431da177e4SLinus Torvalds static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset)
441da177e4SLinus Torvalds {
451da177e4SLinus Torvalds struct buffer_head **bhs = fatent->bhs;
461da177e4SLinus Torvalds if (fatent->nr_bhs == 1) {
471da177e4SLinus Torvalds WARN_ON(offset >= (bhs[0]->b_size - 1));
481da177e4SLinus Torvalds fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
491da177e4SLinus Torvalds fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1);
501da177e4SLinus Torvalds } else {
511da177e4SLinus Torvalds WARN_ON(offset != (bhs[0]->b_size - 1));
521da177e4SLinus Torvalds fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
531da177e4SLinus Torvalds fatent->u.ent12_p[1] = bhs[1]->b_data;
541da177e4SLinus Torvalds }
551da177e4SLinus Torvalds }
561da177e4SLinus Torvalds
fat16_ent_set_ptr(struct fat_entry * fatent,int offset)571da177e4SLinus Torvalds static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset)
581da177e4SLinus Torvalds {
591da177e4SLinus Torvalds WARN_ON(offset & (2 - 1));
601da177e4SLinus Torvalds fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset);
611da177e4SLinus Torvalds }
621da177e4SLinus Torvalds
fat32_ent_set_ptr(struct fat_entry * fatent,int offset)631da177e4SLinus Torvalds static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset)
641da177e4SLinus Torvalds {
651da177e4SLinus Torvalds WARN_ON(offset & (4 - 1));
661da177e4SLinus Torvalds fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset);
671da177e4SLinus Torvalds }
681da177e4SLinus Torvalds
fat12_ent_bread(struct super_block * sb,struct fat_entry * fatent,int offset,sector_t blocknr)691da177e4SLinus Torvalds static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent,
701da177e4SLinus Torvalds int offset, sector_t blocknr)
711da177e4SLinus Torvalds {
721da177e4SLinus Torvalds struct buffer_head **bhs = fatent->bhs;
731da177e4SLinus Torvalds
741da177e4SLinus Torvalds WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
75b522412aSAl Viro fatent->fat_inode = MSDOS_SB(sb)->fat_inode;
76b522412aSAl Viro
771da177e4SLinus Torvalds bhs[0] = sb_bread(sb, blocknr);
781da177e4SLinus Torvalds if (!bhs[0])
791da177e4SLinus Torvalds goto err;
801da177e4SLinus Torvalds
811da177e4SLinus Torvalds if ((offset + 1) < sb->s_blocksize)
821da177e4SLinus Torvalds fatent->nr_bhs = 1;
831da177e4SLinus Torvalds else {
841da177e4SLinus Torvalds /* This entry is block boundary, it needs the next block */
851da177e4SLinus Torvalds blocknr++;
861da177e4SLinus Torvalds bhs[1] = sb_bread(sb, blocknr);
871da177e4SLinus Torvalds if (!bhs[1])
881da177e4SLinus Torvalds goto err_brelse;
891da177e4SLinus Torvalds fatent->nr_bhs = 2;
901da177e4SLinus Torvalds }
911da177e4SLinus Torvalds fat12_ent_set_ptr(fatent, offset);
921da177e4SLinus Torvalds return 0;
931da177e4SLinus Torvalds
941da177e4SLinus Torvalds err_brelse:
951da177e4SLinus Torvalds brelse(bhs[0]);
961da177e4SLinus Torvalds err:
9750c292b4SOGAWA Hirofumi fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)",
9850c292b4SOGAWA Hirofumi (llu)blocknr);
991da177e4SLinus Torvalds return -EIO;
1001da177e4SLinus Torvalds }
1011da177e4SLinus Torvalds
fat_ent_bread(struct super_block * sb,struct fat_entry * fatent,int offset,sector_t blocknr)1021da177e4SLinus Torvalds static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent,
1031da177e4SLinus Torvalds int offset, sector_t blocknr)
1041da177e4SLinus Torvalds {
1058992de4cSJulia Lawall const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
1061da177e4SLinus Torvalds
1071da177e4SLinus Torvalds WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
108b522412aSAl Viro fatent->fat_inode = MSDOS_SB(sb)->fat_inode;
1091da177e4SLinus Torvalds fatent->bhs[0] = sb_bread(sb, blocknr);
1101da177e4SLinus Torvalds if (!fatent->bhs[0]) {
11150c292b4SOGAWA Hirofumi fat_msg_ratelimit(sb, KERN_ERR, "FAT read failed (blocknr %llu)",
112c3302931SOGAWA Hirofumi (llu)blocknr);
1131da177e4SLinus Torvalds return -EIO;
1141da177e4SLinus Torvalds }
1151da177e4SLinus Torvalds fatent->nr_bhs = 1;
1161da177e4SLinus Torvalds ops->ent_set_ptr(fatent, offset);
1171da177e4SLinus Torvalds return 0;
1181da177e4SLinus Torvalds }
1191da177e4SLinus Torvalds
fat12_ent_get(struct fat_entry * fatent)1201da177e4SLinus Torvalds static int fat12_ent_get(struct fat_entry *fatent)
1211da177e4SLinus Torvalds {
1221da177e4SLinus Torvalds u8 **ent12_p = fatent->u.ent12_p;
1231da177e4SLinus Torvalds int next;
1241da177e4SLinus Torvalds
12598283bb4SOGAWA Hirofumi spin_lock(&fat12_entry_lock);
1261da177e4SLinus Torvalds if (fatent->entry & 1)
1271da177e4SLinus Torvalds next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4);
1281da177e4SLinus Torvalds else
1291da177e4SLinus Torvalds next = (*ent12_p[1] << 8) | *ent12_p[0];
13098283bb4SOGAWA Hirofumi spin_unlock(&fat12_entry_lock);
13198283bb4SOGAWA Hirofumi
1321da177e4SLinus Torvalds next &= 0x0fff;
1331da177e4SLinus Torvalds if (next >= BAD_FAT12)
1341da177e4SLinus Torvalds next = FAT_ENT_EOF;
1351da177e4SLinus Torvalds return next;
1361da177e4SLinus Torvalds }
1371da177e4SLinus Torvalds
fat16_ent_get(struct fat_entry * fatent)1381da177e4SLinus Torvalds static int fat16_ent_get(struct fat_entry *fatent)
1391da177e4SLinus Torvalds {
1401da177e4SLinus Torvalds int next = le16_to_cpu(*fatent->u.ent16_p);
1411da177e4SLinus Torvalds WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1));
1421da177e4SLinus Torvalds if (next >= BAD_FAT16)
1431da177e4SLinus Torvalds next = FAT_ENT_EOF;
1441da177e4SLinus Torvalds return next;
1451da177e4SLinus Torvalds }
1461da177e4SLinus Torvalds
fat32_ent_get(struct fat_entry * fatent)1471da177e4SLinus Torvalds static int fat32_ent_get(struct fat_entry *fatent)
1481da177e4SLinus Torvalds {
1491da177e4SLinus Torvalds int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff;
1501da177e4SLinus Torvalds WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1));
1511da177e4SLinus Torvalds if (next >= BAD_FAT32)
1521da177e4SLinus Torvalds next = FAT_ENT_EOF;
1531da177e4SLinus Torvalds return next;
1541da177e4SLinus Torvalds }
1551da177e4SLinus Torvalds
fat12_ent_put(struct fat_entry * fatent,int new)1561da177e4SLinus Torvalds static void fat12_ent_put(struct fat_entry *fatent, int new)
1571da177e4SLinus Torvalds {
1581da177e4SLinus Torvalds u8 **ent12_p = fatent->u.ent12_p;
1591da177e4SLinus Torvalds
1601da177e4SLinus Torvalds if (new == FAT_ENT_EOF)
1611da177e4SLinus Torvalds new = EOF_FAT12;
1621da177e4SLinus Torvalds
16398283bb4SOGAWA Hirofumi spin_lock(&fat12_entry_lock);
1641da177e4SLinus Torvalds if (fatent->entry & 1) {
1651da177e4SLinus Torvalds *ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f);
1661da177e4SLinus Torvalds *ent12_p[1] = new >> 4;
1671da177e4SLinus Torvalds } else {
1681da177e4SLinus Torvalds *ent12_p[0] = new & 0xff;
1691da177e4SLinus Torvalds *ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8);
1701da177e4SLinus Torvalds }
17198283bb4SOGAWA Hirofumi spin_unlock(&fat12_entry_lock);
1721da177e4SLinus Torvalds
173b522412aSAl Viro mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode);
1741da177e4SLinus Torvalds if (fatent->nr_bhs == 2)
175b522412aSAl Viro mark_buffer_dirty_inode(fatent->bhs[1], fatent->fat_inode);
1761da177e4SLinus Torvalds }
1771da177e4SLinus Torvalds
fat16_ent_put(struct fat_entry * fatent,int new)1781da177e4SLinus Torvalds static void fat16_ent_put(struct fat_entry *fatent, int new)
1791da177e4SLinus Torvalds {
1801da177e4SLinus Torvalds if (new == FAT_ENT_EOF)
1811da177e4SLinus Torvalds new = EOF_FAT16;
1821da177e4SLinus Torvalds
1831da177e4SLinus Torvalds *fatent->u.ent16_p = cpu_to_le16(new);
184b522412aSAl Viro mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode);
1851da177e4SLinus Torvalds }
1861da177e4SLinus Torvalds
fat32_ent_put(struct fat_entry * fatent,int new)1871da177e4SLinus Torvalds static void fat32_ent_put(struct fat_entry *fatent, int new)
1881da177e4SLinus Torvalds {
1891da177e4SLinus Torvalds WARN_ON(new & 0xf0000000);
1901da177e4SLinus Torvalds new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff;
1911da177e4SLinus Torvalds *fatent->u.ent32_p = cpu_to_le32(new);
192b522412aSAl Viro mark_buffer_dirty_inode(fatent->bhs[0], fatent->fat_inode);
1931da177e4SLinus Torvalds }
1941da177e4SLinus Torvalds
fat12_ent_next(struct fat_entry * fatent)1951da177e4SLinus Torvalds static int fat12_ent_next(struct fat_entry *fatent)
1961da177e4SLinus Torvalds {
1971da177e4SLinus Torvalds u8 **ent12_p = fatent->u.ent12_p;
1981da177e4SLinus Torvalds struct buffer_head **bhs = fatent->bhs;
1991da177e4SLinus Torvalds u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1);
2001da177e4SLinus Torvalds
2011da177e4SLinus Torvalds fatent->entry++;
2021da177e4SLinus Torvalds if (fatent->nr_bhs == 1) {
203441dff34SCruz Julian Bishop WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data +
204441dff34SCruz Julian Bishop (bhs[0]->b_size - 2)));
205441dff34SCruz Julian Bishop WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data +
206441dff34SCruz Julian Bishop (bhs[0]->b_size - 1)));
2071da177e4SLinus Torvalds if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) {
2081da177e4SLinus Torvalds ent12_p[0] = nextp - 1;
2091da177e4SLinus Torvalds ent12_p[1] = nextp;
2101da177e4SLinus Torvalds return 1;
2111da177e4SLinus Torvalds }
2121da177e4SLinus Torvalds } else {
213441dff34SCruz Julian Bishop WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data +
214441dff34SCruz Julian Bishop (bhs[0]->b_size - 1)));
2151da177e4SLinus Torvalds WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data);
2161da177e4SLinus Torvalds ent12_p[0] = nextp - 1;
2171da177e4SLinus Torvalds ent12_p[1] = nextp;
2181da177e4SLinus Torvalds brelse(bhs[0]);
2191da177e4SLinus Torvalds bhs[0] = bhs[1];
2201da177e4SLinus Torvalds fatent->nr_bhs = 1;
2211da177e4SLinus Torvalds return 1;
2221da177e4SLinus Torvalds }
2231da177e4SLinus Torvalds ent12_p[0] = NULL;
2241da177e4SLinus Torvalds ent12_p[1] = NULL;
2251da177e4SLinus Torvalds return 0;
2261da177e4SLinus Torvalds }
2271da177e4SLinus Torvalds
fat16_ent_next(struct fat_entry * fatent)2281da177e4SLinus Torvalds static int fat16_ent_next(struct fat_entry *fatent)
2291da177e4SLinus Torvalds {
2301da177e4SLinus Torvalds const struct buffer_head *bh = fatent->bhs[0];
2311da177e4SLinus Torvalds fatent->entry++;
2321da177e4SLinus Torvalds if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) {
2331da177e4SLinus Torvalds fatent->u.ent16_p++;
2341da177e4SLinus Torvalds return 1;
2351da177e4SLinus Torvalds }
2361da177e4SLinus Torvalds fatent->u.ent16_p = NULL;
2371da177e4SLinus Torvalds return 0;
2381da177e4SLinus Torvalds }
2391da177e4SLinus Torvalds
fat32_ent_next(struct fat_entry * fatent)2401da177e4SLinus Torvalds static int fat32_ent_next(struct fat_entry *fatent)
2411da177e4SLinus Torvalds {
2421da177e4SLinus Torvalds const struct buffer_head *bh = fatent->bhs[0];
2431da177e4SLinus Torvalds fatent->entry++;
2441da177e4SLinus Torvalds if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) {
2451da177e4SLinus Torvalds fatent->u.ent32_p++;
2461da177e4SLinus Torvalds return 1;
2471da177e4SLinus Torvalds }
2481da177e4SLinus Torvalds fatent->u.ent32_p = NULL;
2491da177e4SLinus Torvalds return 0;
2501da177e4SLinus Torvalds }
2511da177e4SLinus Torvalds
2528992de4cSJulia Lawall static const struct fatent_operations fat12_ops = {
2531da177e4SLinus Torvalds .ent_blocknr = fat12_ent_blocknr,
2541da177e4SLinus Torvalds .ent_set_ptr = fat12_ent_set_ptr,
2551da177e4SLinus Torvalds .ent_bread = fat12_ent_bread,
2561da177e4SLinus Torvalds .ent_get = fat12_ent_get,
2571da177e4SLinus Torvalds .ent_put = fat12_ent_put,
2581da177e4SLinus Torvalds .ent_next = fat12_ent_next,
2591da177e4SLinus Torvalds };
2601da177e4SLinus Torvalds
2618992de4cSJulia Lawall static const struct fatent_operations fat16_ops = {
2621da177e4SLinus Torvalds .ent_blocknr = fat_ent_blocknr,
2631da177e4SLinus Torvalds .ent_set_ptr = fat16_ent_set_ptr,
2641da177e4SLinus Torvalds .ent_bread = fat_ent_bread,
2651da177e4SLinus Torvalds .ent_get = fat16_ent_get,
2661da177e4SLinus Torvalds .ent_put = fat16_ent_put,
2671da177e4SLinus Torvalds .ent_next = fat16_ent_next,
2681da177e4SLinus Torvalds };
2691da177e4SLinus Torvalds
2708992de4cSJulia Lawall static const struct fatent_operations fat32_ops = {
2711da177e4SLinus Torvalds .ent_blocknr = fat_ent_blocknr,
2721da177e4SLinus Torvalds .ent_set_ptr = fat32_ent_set_ptr,
2731da177e4SLinus Torvalds .ent_bread = fat_ent_bread,
2741da177e4SLinus Torvalds .ent_get = fat32_ent_get,
2751da177e4SLinus Torvalds .ent_put = fat32_ent_put,
2761da177e4SLinus Torvalds .ent_next = fat32_ent_next,
2771da177e4SLinus Torvalds };
2781da177e4SLinus Torvalds
lock_fat(struct msdos_sb_info * sbi)2791da177e4SLinus Torvalds static inline void lock_fat(struct msdos_sb_info *sbi)
2801da177e4SLinus Torvalds {
2816b9438e1SArjan van de Ven mutex_lock(&sbi->fat_lock);
2821da177e4SLinus Torvalds }
2831da177e4SLinus Torvalds
unlock_fat(struct msdos_sb_info * sbi)2841da177e4SLinus Torvalds static inline void unlock_fat(struct msdos_sb_info *sbi)
2851da177e4SLinus Torvalds {
2866b9438e1SArjan van de Ven mutex_unlock(&sbi->fat_lock);
2871da177e4SLinus Torvalds }
2881da177e4SLinus Torvalds
fat_ent_access_init(struct super_block * sb)2891da177e4SLinus Torvalds void fat_ent_access_init(struct super_block *sb)
2901da177e4SLinus Torvalds {
2911da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
2921da177e4SLinus Torvalds
2936b9438e1SArjan van de Ven mutex_init(&sbi->fat_lock);
2941da177e4SLinus Torvalds
295306790f7SCarmeli Tamir if (is_fat32(sbi)) {
2961da177e4SLinus Torvalds sbi->fatent_shift = 2;
2971da177e4SLinus Torvalds sbi->fatent_ops = &fat32_ops;
298306790f7SCarmeli Tamir } else if (is_fat16(sbi)) {
2991da177e4SLinus Torvalds sbi->fatent_shift = 1;
3001da177e4SLinus Torvalds sbi->fatent_ops = &fat16_ops;
301306790f7SCarmeli Tamir } else if (is_fat12(sbi)) {
3021da177e4SLinus Torvalds sbi->fatent_shift = -1;
3031da177e4SLinus Torvalds sbi->fatent_ops = &fat12_ops;
304306790f7SCarmeli Tamir } else {
305306790f7SCarmeli Tamir fat_fs_error(sb, "invalid FAT variant, %u bits", sbi->fat_bits);
3061da177e4SLinus Torvalds }
3071da177e4SLinus Torvalds }
3081da177e4SLinus Torvalds
mark_fsinfo_dirty(struct super_block * sb)30990b43665SArtem Bityutskiy static void mark_fsinfo_dirty(struct super_block *sb)
31090b43665SArtem Bityutskiy {
31178491189SArtem Bityutskiy struct msdos_sb_info *sbi = MSDOS_SB(sb);
31278491189SArtem Bityutskiy
313306790f7SCarmeli Tamir if (sb_rdonly(sb) || !is_fat32(sbi))
31478491189SArtem Bityutskiy return;
31578491189SArtem Bityutskiy
31678491189SArtem Bityutskiy __mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC);
31790b43665SArtem Bityutskiy }
31890b43665SArtem Bityutskiy
fat_ent_update_ptr(struct super_block * sb,struct fat_entry * fatent,int offset,sector_t blocknr)3191da177e4SLinus Torvalds static inline int fat_ent_update_ptr(struct super_block *sb,
3201da177e4SLinus Torvalds struct fat_entry *fatent,
3211da177e4SLinus Torvalds int offset, sector_t blocknr)
3221da177e4SLinus Torvalds {
3231da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
3248992de4cSJulia Lawall const struct fatent_operations *ops = sbi->fatent_ops;
3251da177e4SLinus Torvalds struct buffer_head **bhs = fatent->bhs;
3261da177e4SLinus Torvalds
3271da177e4SLinus Torvalds /* Is this fatent's blocks including this entry? */
3281da177e4SLinus Torvalds if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
3291da177e4SLinus Torvalds return 0;
330306790f7SCarmeli Tamir if (is_fat12(sbi)) {
3315e35dd46SOGAWA Hirofumi if ((offset + 1) < sb->s_blocksize) {
3325e35dd46SOGAWA Hirofumi /* This entry is on bhs[0]. */
3335e35dd46SOGAWA Hirofumi if (fatent->nr_bhs == 2) {
3345e35dd46SOGAWA Hirofumi brelse(bhs[1]);
3355e35dd46SOGAWA Hirofumi fatent->nr_bhs = 1;
3365e35dd46SOGAWA Hirofumi }
3375e35dd46SOGAWA Hirofumi } else {
3385e35dd46SOGAWA Hirofumi /* This entry needs the next block. */
3395e35dd46SOGAWA Hirofumi if (fatent->nr_bhs != 2)
3401da177e4SLinus Torvalds return 0;
3415e35dd46SOGAWA Hirofumi if (bhs[1]->b_blocknr != (blocknr + 1))
3425e35dd46SOGAWA Hirofumi return 0;
3435e35dd46SOGAWA Hirofumi }
3441da177e4SLinus Torvalds }
3451da177e4SLinus Torvalds ops->ent_set_ptr(fatent, offset);
3461da177e4SLinus Torvalds return 1;
3471da177e4SLinus Torvalds }
3481da177e4SLinus Torvalds
fat_ent_read(struct inode * inode,struct fat_entry * fatent,int entry)3491da177e4SLinus Torvalds int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry)
3501da177e4SLinus Torvalds {
3511da177e4SLinus Torvalds struct super_block *sb = inode->i_sb;
3521da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
3538992de4cSJulia Lawall const struct fatent_operations *ops = sbi->fatent_ops;
3541da177e4SLinus Torvalds int err, offset;
3551da177e4SLinus Torvalds sector_t blocknr;
3561da177e4SLinus Torvalds
3570afa9626SOGAWA Hirofumi if (!fat_valid_entry(sbi, entry)) {
3581da177e4SLinus Torvalds fatent_brelse(fatent);
35985c78591SDenis Karpov fat_fs_error(sb, "invalid access to FAT (entry 0x%08x)", entry);
3601da177e4SLinus Torvalds return -EIO;
3611da177e4SLinus Torvalds }
3621da177e4SLinus Torvalds
3631da177e4SLinus Torvalds fatent_set_entry(fatent, entry);
3641da177e4SLinus Torvalds ops->ent_blocknr(sb, entry, &offset, &blocknr);
3651da177e4SLinus Torvalds
3661da177e4SLinus Torvalds if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) {
3671da177e4SLinus Torvalds fatent_brelse(fatent);
3681da177e4SLinus Torvalds err = ops->ent_bread(sb, fatent, offset, blocknr);
3691da177e4SLinus Torvalds if (err)
3701da177e4SLinus Torvalds return err;
3711da177e4SLinus Torvalds }
3721da177e4SLinus Torvalds return ops->ent_get(fatent);
3731da177e4SLinus Torvalds }
3741da177e4SLinus Torvalds
3751da177e4SLinus Torvalds /* FIXME: We can write the blocks as more big chunk. */
fat_mirror_bhs(struct super_block * sb,struct buffer_head ** bhs,int nr_bhs)3761da177e4SLinus Torvalds static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs,
3771da177e4SLinus Torvalds int nr_bhs)
3781da177e4SLinus Torvalds {
3791da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
3801da177e4SLinus Torvalds struct buffer_head *c_bh;
3811da177e4SLinus Torvalds int err, n, copy;
3821da177e4SLinus Torvalds
3831da177e4SLinus Torvalds err = 0;
3841da177e4SLinus Torvalds for (copy = 1; copy < sbi->fats; copy++) {
3851da177e4SLinus Torvalds sector_t backup_fat = sbi->fat_length * copy;
3861da177e4SLinus Torvalds
3871da177e4SLinus Torvalds for (n = 0; n < nr_bhs; n++) {
3881da177e4SLinus Torvalds c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr);
3891da177e4SLinus Torvalds if (!c_bh) {
3901da177e4SLinus Torvalds err = -ENOMEM;
3911da177e4SLinus Torvalds goto error;
3921da177e4SLinus Torvalds }
39307bfa441SOGAWA Hirofumi /* Avoid race with userspace read via bdev */
39407bfa441SOGAWA Hirofumi lock_buffer(c_bh);
3951da177e4SLinus Torvalds memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize);
3961da177e4SLinus Torvalds set_buffer_uptodate(c_bh);
39707bfa441SOGAWA Hirofumi unlock_buffer(c_bh);
398b522412aSAl Viro mark_buffer_dirty_inode(c_bh, sbi->fat_inode);
3991751e8a6SLinus Torvalds if (sb->s_flags & SB_SYNCHRONOUS)
4001da177e4SLinus Torvalds err = sync_dirty_buffer(c_bh);
4011da177e4SLinus Torvalds brelse(c_bh);
4021da177e4SLinus Torvalds if (err)
4031da177e4SLinus Torvalds goto error;
4041da177e4SLinus Torvalds }
4051da177e4SLinus Torvalds }
4061da177e4SLinus Torvalds error:
4071da177e4SLinus Torvalds return err;
4081da177e4SLinus Torvalds }
4091da177e4SLinus Torvalds
fat_ent_write(struct inode * inode,struct fat_entry * fatent,int new,int wait)4101da177e4SLinus Torvalds int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
4111da177e4SLinus Torvalds int new, int wait)
4121da177e4SLinus Torvalds {
4131da177e4SLinus Torvalds struct super_block *sb = inode->i_sb;
4148992de4cSJulia Lawall const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
4151da177e4SLinus Torvalds int err;
4161da177e4SLinus Torvalds
4171da177e4SLinus Torvalds ops->ent_put(fatent, new);
4181da177e4SLinus Torvalds if (wait) {
4191da177e4SLinus Torvalds err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs);
4201da177e4SLinus Torvalds if (err)
4211da177e4SLinus Torvalds return err;
4221da177e4SLinus Torvalds }
4231da177e4SLinus Torvalds return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs);
4241da177e4SLinus Torvalds }
4251da177e4SLinus Torvalds
fat_ent_next(struct msdos_sb_info * sbi,struct fat_entry * fatent)4261da177e4SLinus Torvalds static inline int fat_ent_next(struct msdos_sb_info *sbi,
4271da177e4SLinus Torvalds struct fat_entry *fatent)
4281da177e4SLinus Torvalds {
4291da177e4SLinus Torvalds if (sbi->fatent_ops->ent_next(fatent)) {
4301da177e4SLinus Torvalds if (fatent->entry < sbi->max_cluster)
4311da177e4SLinus Torvalds return 1;
4321da177e4SLinus Torvalds }
4331da177e4SLinus Torvalds return 0;
4341da177e4SLinus Torvalds }
4351da177e4SLinus Torvalds
fat_ent_read_block(struct super_block * sb,struct fat_entry * fatent)4361da177e4SLinus Torvalds static inline int fat_ent_read_block(struct super_block *sb,
4371da177e4SLinus Torvalds struct fat_entry *fatent)
4381da177e4SLinus Torvalds {
4398992de4cSJulia Lawall const struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
4401da177e4SLinus Torvalds sector_t blocknr;
4411da177e4SLinus Torvalds int offset;
4421da177e4SLinus Torvalds
4431da177e4SLinus Torvalds fatent_brelse(fatent);
4441da177e4SLinus Torvalds ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
4451da177e4SLinus Torvalds return ops->ent_bread(sb, fatent, offset, blocknr);
4461da177e4SLinus Torvalds }
4471da177e4SLinus Torvalds
fat_collect_bhs(struct buffer_head ** bhs,int * nr_bhs,struct fat_entry * fatent)4481da177e4SLinus Torvalds static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs,
4491da177e4SLinus Torvalds struct fat_entry *fatent)
4501da177e4SLinus Torvalds {
4511da177e4SLinus Torvalds int n, i;
4521da177e4SLinus Torvalds
4531da177e4SLinus Torvalds for (n = 0; n < fatent->nr_bhs; n++) {
4541da177e4SLinus Torvalds for (i = 0; i < *nr_bhs; i++) {
4551da177e4SLinus Torvalds if (fatent->bhs[n] == bhs[i])
4561da177e4SLinus Torvalds break;
4571da177e4SLinus Torvalds }
4581da177e4SLinus Torvalds if (i == *nr_bhs) {
4591da177e4SLinus Torvalds get_bh(fatent->bhs[n]);
4601da177e4SLinus Torvalds bhs[i] = fatent->bhs[n];
4611da177e4SLinus Torvalds (*nr_bhs)++;
4621da177e4SLinus Torvalds }
4631da177e4SLinus Torvalds }
4641da177e4SLinus Torvalds }
4651da177e4SLinus Torvalds
fat_alloc_clusters(struct inode * inode,int * cluster,int nr_cluster)4661da177e4SLinus Torvalds int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
4671da177e4SLinus Torvalds {
4681da177e4SLinus Torvalds struct super_block *sb = inode->i_sb;
4691da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
4708992de4cSJulia Lawall const struct fatent_operations *ops = sbi->fatent_ops;
4711da177e4SLinus Torvalds struct fat_entry fatent, prev_ent;
4721da177e4SLinus Torvalds struct buffer_head *bhs[MAX_BUF_PER_PAGE];
4731da177e4SLinus Torvalds int i, count, err, nr_bhs, idx_clus;
4741da177e4SLinus Torvalds
4751da177e4SLinus Torvalds BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2)); /* fixed limit */
4761da177e4SLinus Torvalds
4771da177e4SLinus Torvalds lock_fat(sbi);
478606e423eSOGAWA Hirofumi if (sbi->free_clusters != -1 && sbi->free_clus_valid &&
479606e423eSOGAWA Hirofumi sbi->free_clusters < nr_cluster) {
4801da177e4SLinus Torvalds unlock_fat(sbi);
4811da177e4SLinus Torvalds return -ENOSPC;
4821da177e4SLinus Torvalds }
4831da177e4SLinus Torvalds
4841da177e4SLinus Torvalds err = nr_bhs = idx_clus = 0;
4851da177e4SLinus Torvalds count = FAT_START_ENT;
4861da177e4SLinus Torvalds fatent_init(&prev_ent);
4871da177e4SLinus Torvalds fatent_init(&fatent);
4881da177e4SLinus Torvalds fatent_set_entry(&fatent, sbi->prev_free + 1);
4891da177e4SLinus Torvalds while (count < sbi->max_cluster) {
4901da177e4SLinus Torvalds if (fatent.entry >= sbi->max_cluster)
4911da177e4SLinus Torvalds fatent.entry = FAT_START_ENT;
4921da177e4SLinus Torvalds fatent_set_entry(&fatent, fatent.entry);
4931da177e4SLinus Torvalds err = fat_ent_read_block(sb, &fatent);
4941da177e4SLinus Torvalds if (err)
4951da177e4SLinus Torvalds goto out;
4961da177e4SLinus Torvalds
4971da177e4SLinus Torvalds /* Find the free entries in a block */
4981da177e4SLinus Torvalds do {
4991da177e4SLinus Torvalds if (ops->ent_get(&fatent) == FAT_ENT_FREE) {
5001da177e4SLinus Torvalds int entry = fatent.entry;
5011da177e4SLinus Torvalds
5021da177e4SLinus Torvalds /* make the cluster chain */
5031da177e4SLinus Torvalds ops->ent_put(&fatent, FAT_ENT_EOF);
5041da177e4SLinus Torvalds if (prev_ent.nr_bhs)
5051da177e4SLinus Torvalds ops->ent_put(&prev_ent, entry);
5061da177e4SLinus Torvalds
5071da177e4SLinus Torvalds fat_collect_bhs(bhs, &nr_bhs, &fatent);
5081da177e4SLinus Torvalds
5091da177e4SLinus Torvalds sbi->prev_free = entry;
5101da177e4SLinus Torvalds if (sbi->free_clusters != -1)
5111da177e4SLinus Torvalds sbi->free_clusters--;
5121da177e4SLinus Torvalds
5131da177e4SLinus Torvalds cluster[idx_clus] = entry;
5141da177e4SLinus Torvalds idx_clus++;
5151da177e4SLinus Torvalds if (idx_clus == nr_cluster)
5161da177e4SLinus Torvalds goto out;
5171da177e4SLinus Torvalds
5181da177e4SLinus Torvalds /*
5191da177e4SLinus Torvalds * fat_collect_bhs() gets ref-count of bhs,
5201da177e4SLinus Torvalds * so we can still use the prev_ent.
5211da177e4SLinus Torvalds */
5221da177e4SLinus Torvalds prev_ent = fatent;
5231da177e4SLinus Torvalds }
5241da177e4SLinus Torvalds count++;
5251da177e4SLinus Torvalds if (count == sbi->max_cluster)
5261da177e4SLinus Torvalds break;
5271da177e4SLinus Torvalds } while (fat_ent_next(sbi, &fatent));
5281da177e4SLinus Torvalds }
5291da177e4SLinus Torvalds
5301da177e4SLinus Torvalds /* Couldn't allocate the free entries */
5311da177e4SLinus Torvalds sbi->free_clusters = 0;
532606e423eSOGAWA Hirofumi sbi->free_clus_valid = 1;
5331da177e4SLinus Torvalds err = -ENOSPC;
5341da177e4SLinus Torvalds
5351da177e4SLinus Torvalds out:
5361da177e4SLinus Torvalds unlock_fat(sbi);
537330fe3c4SArtem Bityutskiy mark_fsinfo_dirty(sb);
5381da177e4SLinus Torvalds fatent_brelse(&fatent);
5391da177e4SLinus Torvalds if (!err) {
5401da177e4SLinus Torvalds if (inode_needs_sync(inode))
5411da177e4SLinus Torvalds err = fat_sync_bhs(bhs, nr_bhs);
5421da177e4SLinus Torvalds if (!err)
5431da177e4SLinus Torvalds err = fat_mirror_bhs(sb, bhs, nr_bhs);
5441da177e4SLinus Torvalds }
5451da177e4SLinus Torvalds for (i = 0; i < nr_bhs; i++)
5461da177e4SLinus Torvalds brelse(bhs[i]);
5471da177e4SLinus Torvalds
5481da177e4SLinus Torvalds if (err && idx_clus)
5491da177e4SLinus Torvalds fat_free_clusters(inode, cluster[0]);
5501da177e4SLinus Torvalds
5511da177e4SLinus Torvalds return err;
5521da177e4SLinus Torvalds }
5531da177e4SLinus Torvalds
fat_free_clusters(struct inode * inode,int cluster)5541da177e4SLinus Torvalds int fat_free_clusters(struct inode *inode, int cluster)
5551da177e4SLinus Torvalds {
5561da177e4SLinus Torvalds struct super_block *sb = inode->i_sb;
5571da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
5588992de4cSJulia Lawall const struct fatent_operations *ops = sbi->fatent_ops;
5591da177e4SLinus Torvalds struct fat_entry fatent;
5601da177e4SLinus Torvalds struct buffer_head *bhs[MAX_BUF_PER_PAGE];
5611da177e4SLinus Torvalds int i, err, nr_bhs;
562330fe3c4SArtem Bityutskiy int first_cl = cluster, dirty_fsinfo = 0;
5631da177e4SLinus Torvalds
5641da177e4SLinus Torvalds nr_bhs = 0;
5651da177e4SLinus Torvalds fatent_init(&fatent);
5661da177e4SLinus Torvalds lock_fat(sbi);
5671da177e4SLinus Torvalds do {
5681da177e4SLinus Torvalds cluster = fat_ent_read(inode, &fatent, cluster);
5691da177e4SLinus Torvalds if (cluster < 0) {
5701da177e4SLinus Torvalds err = cluster;
5711da177e4SLinus Torvalds goto error;
5721da177e4SLinus Torvalds } else if (cluster == FAT_ENT_FREE) {
57385c78591SDenis Karpov fat_fs_error(sb, "%s: deleting FAT entry beyond EOF",
5748e24eea7SHarvey Harrison __func__);
5751da177e4SLinus Torvalds err = -EIO;
5761da177e4SLinus Torvalds goto error;
5771da177e4SLinus Torvalds }
5781da177e4SLinus Torvalds
579681142f9SChristoph Hellwig if (sbi->options.discard) {
5808c540a96SDavid Woodhouse /*
581681142f9SChristoph Hellwig * Issue discard for the sectors we no longer
582681142f9SChristoph Hellwig * care about, batching contiguous clusters
583681142f9SChristoph Hellwig * into one request
5848c540a96SDavid Woodhouse */
5858c540a96SDavid Woodhouse if (cluster != fatent.entry + 1) {
5868c540a96SDavid Woodhouse int nr_clus = fatent.entry - first_cl + 1;
5878c540a96SDavid Woodhouse
588681142f9SChristoph Hellwig sb_issue_discard(sb,
589681142f9SChristoph Hellwig fat_clus_to_blknr(sbi, first_cl),
5902cf6d26aSChristoph Hellwig nr_clus * sbi->sec_per_clus,
591dd3932edSChristoph Hellwig GFP_NOFS, 0);
592681142f9SChristoph Hellwig
5938c540a96SDavid Woodhouse first_cl = cluster;
5948c540a96SDavid Woodhouse }
595681142f9SChristoph Hellwig }
5968c540a96SDavid Woodhouse
5971da177e4SLinus Torvalds ops->ent_put(&fatent, FAT_ENT_FREE);
598a6bf6b21SOGAWA Hirofumi if (sbi->free_clusters != -1) {
5991da177e4SLinus Torvalds sbi->free_clusters++;
600330fe3c4SArtem Bityutskiy dirty_fsinfo = 1;
601a6bf6b21SOGAWA Hirofumi }
6021da177e4SLinus Torvalds
6031da177e4SLinus Torvalds if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) {
6041751e8a6SLinus Torvalds if (sb->s_flags & SB_SYNCHRONOUS) {
6051da177e4SLinus Torvalds err = fat_sync_bhs(bhs, nr_bhs);
6061da177e4SLinus Torvalds if (err)
6071da177e4SLinus Torvalds goto error;
6081da177e4SLinus Torvalds }
6091da177e4SLinus Torvalds err = fat_mirror_bhs(sb, bhs, nr_bhs);
6101da177e4SLinus Torvalds if (err)
6111da177e4SLinus Torvalds goto error;
6121da177e4SLinus Torvalds for (i = 0; i < nr_bhs; i++)
6131da177e4SLinus Torvalds brelse(bhs[i]);
6141da177e4SLinus Torvalds nr_bhs = 0;
6151da177e4SLinus Torvalds }
6161da177e4SLinus Torvalds fat_collect_bhs(bhs, &nr_bhs, &fatent);
6171da177e4SLinus Torvalds } while (cluster != FAT_ENT_EOF);
6181da177e4SLinus Torvalds
6191751e8a6SLinus Torvalds if (sb->s_flags & SB_SYNCHRONOUS) {
6201da177e4SLinus Torvalds err = fat_sync_bhs(bhs, nr_bhs);
6211da177e4SLinus Torvalds if (err)
6221da177e4SLinus Torvalds goto error;
6231da177e4SLinus Torvalds }
6241da177e4SLinus Torvalds err = fat_mirror_bhs(sb, bhs, nr_bhs);
6251da177e4SLinus Torvalds error:
6261da177e4SLinus Torvalds fatent_brelse(&fatent);
6271da177e4SLinus Torvalds for (i = 0; i < nr_bhs; i++)
6281da177e4SLinus Torvalds brelse(bhs[i]);
6291da177e4SLinus Torvalds unlock_fat(sbi);
630330fe3c4SArtem Bityutskiy if (dirty_fsinfo)
631330fe3c4SArtem Bityutskiy mark_fsinfo_dirty(sb);
6321da177e4SLinus Torvalds
6331da177e4SLinus Torvalds return err;
6341da177e4SLinus Torvalds }
6357c709d00SOGAWA Hirofumi EXPORT_SYMBOL_GPL(fat_free_clusters);
6361da177e4SLinus Torvalds
63789831003SOGAWA Hirofumi struct fatent_ra {
63889831003SOGAWA Hirofumi sector_t cur;
63989831003SOGAWA Hirofumi sector_t limit;
6409f966be8SOGAWA Hirofumi
64189831003SOGAWA Hirofumi unsigned int ra_blocks;
64289831003SOGAWA Hirofumi sector_t ra_advance;
64389831003SOGAWA Hirofumi sector_t ra_next;
64489831003SOGAWA Hirofumi sector_t ra_limit;
64589831003SOGAWA Hirofumi };
64689831003SOGAWA Hirofumi
fat_ra_init(struct super_block * sb,struct fatent_ra * ra,struct fat_entry * fatent,int ent_limit)64789831003SOGAWA Hirofumi static void fat_ra_init(struct super_block *sb, struct fatent_ra *ra,
64889831003SOGAWA Hirofumi struct fat_entry *fatent, int ent_limit)
6499f966be8SOGAWA Hirofumi {
65089831003SOGAWA Hirofumi struct msdos_sb_info *sbi = MSDOS_SB(sb);
65189831003SOGAWA Hirofumi const struct fatent_operations *ops = sbi->fatent_ops;
65289831003SOGAWA Hirofumi sector_t blocknr, block_end;
65389831003SOGAWA Hirofumi int offset;
65489831003SOGAWA Hirofumi /*
65589831003SOGAWA Hirofumi * This is the sequential read, so ra_pages * 2 (but try to
65689831003SOGAWA Hirofumi * align the optimal hardware IO size).
65789831003SOGAWA Hirofumi * [BTW, 128kb covers the whole sectors for FAT12 and FAT16]
65889831003SOGAWA Hirofumi */
65989831003SOGAWA Hirofumi unsigned long ra_pages = sb->s_bdi->ra_pages;
66089831003SOGAWA Hirofumi unsigned int reada_blocks;
66189831003SOGAWA Hirofumi
662a090a5a7SOGAWA Hirofumi if (fatent->entry >= ent_limit)
663a090a5a7SOGAWA Hirofumi return;
664a090a5a7SOGAWA Hirofumi
66589831003SOGAWA Hirofumi if (ra_pages > sb->s_bdi->io_pages)
66689831003SOGAWA Hirofumi ra_pages = rounddown(ra_pages, sb->s_bdi->io_pages);
66789831003SOGAWA Hirofumi reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1);
66889831003SOGAWA Hirofumi
66989831003SOGAWA Hirofumi /* Initialize the range for sequential read */
67089831003SOGAWA Hirofumi ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
67189831003SOGAWA Hirofumi ops->ent_blocknr(sb, ent_limit - 1, &offset, &block_end);
67289831003SOGAWA Hirofumi ra->cur = 0;
67389831003SOGAWA Hirofumi ra->limit = (block_end + 1) - blocknr;
67489831003SOGAWA Hirofumi
67589831003SOGAWA Hirofumi /* Advancing the window at half size */
67689831003SOGAWA Hirofumi ra->ra_blocks = reada_blocks >> 1;
67789831003SOGAWA Hirofumi ra->ra_advance = ra->cur;
67889831003SOGAWA Hirofumi ra->ra_next = ra->cur;
67989831003SOGAWA Hirofumi ra->ra_limit = ra->cur + min_t(sector_t, reada_blocks, ra->limit);
68089831003SOGAWA Hirofumi }
68189831003SOGAWA Hirofumi
68289831003SOGAWA Hirofumi /* Assuming to be called before reading a new block (increments ->cur). */
fat_ent_reada(struct super_block * sb,struct fatent_ra * ra,struct fat_entry * fatent)68389831003SOGAWA Hirofumi static void fat_ent_reada(struct super_block *sb, struct fatent_ra *ra,
68489831003SOGAWA Hirofumi struct fat_entry *fatent)
68589831003SOGAWA Hirofumi {
68689831003SOGAWA Hirofumi if (ra->ra_next >= ra->ra_limit)
68789831003SOGAWA Hirofumi return;
68889831003SOGAWA Hirofumi
68989831003SOGAWA Hirofumi if (ra->cur >= ra->ra_advance) {
69089831003SOGAWA Hirofumi struct msdos_sb_info *sbi = MSDOS_SB(sb);
69189831003SOGAWA Hirofumi const struct fatent_operations *ops = sbi->fatent_ops;
69289831003SOGAWA Hirofumi struct blk_plug plug;
69389831003SOGAWA Hirofumi sector_t blocknr, diff;
69489831003SOGAWA Hirofumi int offset;
6959f966be8SOGAWA Hirofumi
6969f966be8SOGAWA Hirofumi ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
6979f966be8SOGAWA Hirofumi
69889831003SOGAWA Hirofumi diff = blocknr - ra->cur;
69989831003SOGAWA Hirofumi blk_start_plug(&plug);
70089831003SOGAWA Hirofumi /*
70189831003SOGAWA Hirofumi * FIXME: we would want to directly use the bio with
70289831003SOGAWA Hirofumi * pages to reduce the number of segments.
70389831003SOGAWA Hirofumi */
70489831003SOGAWA Hirofumi for (; ra->ra_next < ra->ra_limit; ra->ra_next++)
70589831003SOGAWA Hirofumi sb_breadahead(sb, ra->ra_next + diff);
70689831003SOGAWA Hirofumi blk_finish_plug(&plug);
70789831003SOGAWA Hirofumi
70889831003SOGAWA Hirofumi /* Advance the readahead window */
70989831003SOGAWA Hirofumi ra->ra_advance += ra->ra_blocks;
71089831003SOGAWA Hirofumi ra->ra_limit += min_t(sector_t,
71189831003SOGAWA Hirofumi ra->ra_blocks, ra->limit - ra->ra_limit);
71289831003SOGAWA Hirofumi }
71389831003SOGAWA Hirofumi ra->cur++;
7149f966be8SOGAWA Hirofumi }
7159f966be8SOGAWA Hirofumi
fat_count_free_clusters(struct super_block * sb)7161da177e4SLinus Torvalds int fat_count_free_clusters(struct super_block *sb)
7171da177e4SLinus Torvalds {
7181da177e4SLinus Torvalds struct msdos_sb_info *sbi = MSDOS_SB(sb);
7198992de4cSJulia Lawall const struct fatent_operations *ops = sbi->fatent_ops;
7201da177e4SLinus Torvalds struct fat_entry fatent;
72189831003SOGAWA Hirofumi struct fatent_ra fatent_ra;
7221da177e4SLinus Torvalds int err = 0, free;
7231da177e4SLinus Torvalds
7241da177e4SLinus Torvalds lock_fat(sbi);
725606e423eSOGAWA Hirofumi if (sbi->free_clusters != -1 && sbi->free_clus_valid)
7261da177e4SLinus Torvalds goto out;
7271da177e4SLinus Torvalds
7281da177e4SLinus Torvalds free = 0;
7291da177e4SLinus Torvalds fatent_init(&fatent);
7301da177e4SLinus Torvalds fatent_set_entry(&fatent, FAT_START_ENT);
73189831003SOGAWA Hirofumi fat_ra_init(sb, &fatent_ra, &fatent, sbi->max_cluster);
7321da177e4SLinus Torvalds while (fatent.entry < sbi->max_cluster) {
7339f966be8SOGAWA Hirofumi /* readahead of fat blocks */
73489831003SOGAWA Hirofumi fat_ent_reada(sb, &fatent_ra, &fatent);
7359f966be8SOGAWA Hirofumi
7361da177e4SLinus Torvalds err = fat_ent_read_block(sb, &fatent);
7371da177e4SLinus Torvalds if (err)
7381da177e4SLinus Torvalds goto out;
7391da177e4SLinus Torvalds
7401da177e4SLinus Torvalds do {
7411da177e4SLinus Torvalds if (ops->ent_get(&fatent) == FAT_ENT_FREE)
7421da177e4SLinus Torvalds free++;
7431da177e4SLinus Torvalds } while (fat_ent_next(sbi, &fatent));
744ac081c3bSKhazhismel Kumykov cond_resched();
7451da177e4SLinus Torvalds }
7461da177e4SLinus Torvalds sbi->free_clusters = free;
747606e423eSOGAWA Hirofumi sbi->free_clus_valid = 1;
74890b43665SArtem Bityutskiy mark_fsinfo_dirty(sb);
7491da177e4SLinus Torvalds fatent_brelse(&fatent);
7501da177e4SLinus Torvalds out:
7511da177e4SLinus Torvalds unlock_fat(sbi);
7521da177e4SLinus Torvalds return err;
7531da177e4SLinus Torvalds }
754f663b5b3SWentao Wang
fat_trim_clusters(struct super_block * sb,u32 clus,u32 nr_clus)755f663b5b3SWentao Wang static int fat_trim_clusters(struct super_block *sb, u32 clus, u32 nr_clus)
756f663b5b3SWentao Wang {
757f663b5b3SWentao Wang struct msdos_sb_info *sbi = MSDOS_SB(sb);
758f663b5b3SWentao Wang return sb_issue_discard(sb, fat_clus_to_blknr(sbi, clus),
759f663b5b3SWentao Wang nr_clus * sbi->sec_per_clus, GFP_NOFS, 0);
760f663b5b3SWentao Wang }
761f663b5b3SWentao Wang
fat_trim_fs(struct inode * inode,struct fstrim_range * range)762f663b5b3SWentao Wang int fat_trim_fs(struct inode *inode, struct fstrim_range *range)
763f663b5b3SWentao Wang {
764f663b5b3SWentao Wang struct super_block *sb = inode->i_sb;
765f663b5b3SWentao Wang struct msdos_sb_info *sbi = MSDOS_SB(sb);
766f663b5b3SWentao Wang const struct fatent_operations *ops = sbi->fatent_ops;
767f663b5b3SWentao Wang struct fat_entry fatent;
76889831003SOGAWA Hirofumi struct fatent_ra fatent_ra;
769f663b5b3SWentao Wang u64 ent_start, ent_end, minlen, trimmed = 0;
770f663b5b3SWentao Wang u32 free = 0;
771f663b5b3SWentao Wang int err = 0;
772f663b5b3SWentao Wang
773f663b5b3SWentao Wang /*
774f663b5b3SWentao Wang * FAT data is organized as clusters, trim at the granulary of cluster.
775f663b5b3SWentao Wang *
776a109ae2aSdingsenjie * fstrim_range is in byte, convert values to cluster index.
777f663b5b3SWentao Wang * Treat sectors before data region as all used, not to trim them.
778f663b5b3SWentao Wang */
779f663b5b3SWentao Wang ent_start = max_t(u64, range->start>>sbi->cluster_bits, FAT_START_ENT);
780f663b5b3SWentao Wang ent_end = ent_start + (range->len >> sbi->cluster_bits) - 1;
781f663b5b3SWentao Wang minlen = range->minlen >> sbi->cluster_bits;
782f663b5b3SWentao Wang
783f663b5b3SWentao Wang if (ent_start >= sbi->max_cluster || range->len < sbi->cluster_size)
784f663b5b3SWentao Wang return -EINVAL;
785f663b5b3SWentao Wang if (ent_end >= sbi->max_cluster)
786f663b5b3SWentao Wang ent_end = sbi->max_cluster - 1;
787f663b5b3SWentao Wang
788f663b5b3SWentao Wang fatent_init(&fatent);
789f663b5b3SWentao Wang lock_fat(sbi);
790f663b5b3SWentao Wang fatent_set_entry(&fatent, ent_start);
79189831003SOGAWA Hirofumi fat_ra_init(sb, &fatent_ra, &fatent, ent_end + 1);
792f663b5b3SWentao Wang while (fatent.entry <= ent_end) {
793f663b5b3SWentao Wang /* readahead of fat blocks */
79489831003SOGAWA Hirofumi fat_ent_reada(sb, &fatent_ra, &fatent);
795f663b5b3SWentao Wang
796f663b5b3SWentao Wang err = fat_ent_read_block(sb, &fatent);
797f663b5b3SWentao Wang if (err)
798f663b5b3SWentao Wang goto error;
799f663b5b3SWentao Wang do {
800f663b5b3SWentao Wang if (ops->ent_get(&fatent) == FAT_ENT_FREE) {
801f663b5b3SWentao Wang free++;
802f663b5b3SWentao Wang } else if (free) {
803f663b5b3SWentao Wang if (free >= minlen) {
804f663b5b3SWentao Wang u32 clus = fatent.entry - free;
805f663b5b3SWentao Wang
806f663b5b3SWentao Wang err = fat_trim_clusters(sb, clus, free);
807f663b5b3SWentao Wang if (err && err != -EOPNOTSUPP)
808f663b5b3SWentao Wang goto error;
809f663b5b3SWentao Wang if (!err)
810f663b5b3SWentao Wang trimmed += free;
811f663b5b3SWentao Wang err = 0;
812f663b5b3SWentao Wang }
813f663b5b3SWentao Wang free = 0;
814f663b5b3SWentao Wang }
815f663b5b3SWentao Wang } while (fat_ent_next(sbi, &fatent) && fatent.entry <= ent_end);
816f663b5b3SWentao Wang
817f663b5b3SWentao Wang if (fatal_signal_pending(current)) {
818f663b5b3SWentao Wang err = -ERESTARTSYS;
819f663b5b3SWentao Wang goto error;
820f663b5b3SWentao Wang }
821f663b5b3SWentao Wang
822f663b5b3SWentao Wang if (need_resched()) {
823f663b5b3SWentao Wang fatent_brelse(&fatent);
824f663b5b3SWentao Wang unlock_fat(sbi);
825f663b5b3SWentao Wang cond_resched();
826f663b5b3SWentao Wang lock_fat(sbi);
827f663b5b3SWentao Wang }
828f663b5b3SWentao Wang }
829f663b5b3SWentao Wang /* handle scenario when tail entries are all free */
830f663b5b3SWentao Wang if (free && free >= minlen) {
831f663b5b3SWentao Wang u32 clus = fatent.entry - free;
832f663b5b3SWentao Wang
833f663b5b3SWentao Wang err = fat_trim_clusters(sb, clus, free);
834f663b5b3SWentao Wang if (err && err != -EOPNOTSUPP)
835f663b5b3SWentao Wang goto error;
836f663b5b3SWentao Wang if (!err)
837f663b5b3SWentao Wang trimmed += free;
838f663b5b3SWentao Wang err = 0;
839f663b5b3SWentao Wang }
840f663b5b3SWentao Wang
841f663b5b3SWentao Wang error:
842f663b5b3SWentao Wang fatent_brelse(&fatent);
843f663b5b3SWentao Wang unlock_fat(sbi);
844f663b5b3SWentao Wang
845f663b5b3SWentao Wang range->len = trimmed << sbi->cluster_bits;
846f663b5b3SWentao Wang
847f663b5b3SWentao Wang return err;
848f663b5b3SWentao Wang }
849